Paste wax.. I have some used by museums called Renaissance Wax. It's an excellent preservative. I think if you buy a floor wax it will work as well, but must not have Carnuba in it. I hope someone can verifiy this.
Also, I have had excellent cleaning results using Flitz rather than Brasso, even though I am shining up grip frames, not a 66 (mine is antiqued).
Hope this helps, amigo.